This present invention generally relates to a method and system of visualizing paint on a computer-generated object, and more specifically, to a method and system of visualizing automotive paint on a computer-generated vehicle design.
BACKGROUND OF THE INVENTION
Simulation of paint using computer-generated images allows rapid, cost-effective evaluation of the paint in anticipation of a final painted product. However, rendering of paint on objects such as automotive vehicles has yet to be realistic. A realistic rendering would capture reflections, highlights and color travel as the surfaces are illuminated by the sun, under ambient light, and in various environments. A realistic simulation would convey accurately what the actual painted product would look like. Conversely, a realistic simulation would allow a real paint to be identified by the paint color and characteristics from the image. Realistic simulation would aid designers in the selection of paint for a product offering and consumers in the choice of color on their new car or truck.
Traditional methods of evaluating paint on a mobile vehicle are time consuming, expensive and sometimes inefficient. One method is to obtain a real vehicle, paint it, and arrange for showing it. Sometimes there may be no vehicle available yet, for example, if the vehicle is in the process of being designed. Only math data or a surface description, for example, may be available. Alternatively, instead of a real vehicle an expensive clay model may be obtained. The clay model may be made and painted although the surfaces may be subject to change. Hard model evaluations require xe2x80x9cfreezingxe2x80x9d a design, preventing the paint from being assessed rapidly when even minor changes in vehicle features occur. Evaluation of paint on full-size vehicles may be very costly and time consuming, and may present difficulties with storage and transport of models for wider audience viewing. Moreover, evaluation of an entire palette of paint colors and types becomes unwieldy.
A second method is to use individual paint chips or painted and contoured samples called xe2x80x9cspeed shapesxe2x80x9d, that may provide an impression of how an individual paint will look on a finished vehicle. However, smaller samples do not quite provide the full appreciation of what a final painted vehicle would look like, although color and feature analysis of an individual paint chip or sample may be utilized as a starting point for a realistic paint simulation.
A third method involves evaluation of replicated and retouched photographs of real vehicles painted with given paints. The retouched photographs may have different colors and may be used to provide a set of photographs for the same vehicle design re-painted with different colors. Retouching of the photograph may not result in accurate rendering of a paint that has compositions and characteristics such as flakes. If the original photograph represents a vehicle painted with a solid paint, it is quite difficult to retouch the original photograph to show the highlights and effects that are created by paints with flakes. Photographs of a vehicle show only a static view of the vehicle. Retouched photographs are dependent heavily on subjective judgment of the person who does the rendering and color image retouching, and are dependent on a color gamut of the printing media. Also, they do not provide enough correct visual queues to visualize the whole vehicle, especially from a variety of different viewing positions.
Accurate simulation and rendering with virtual paint has many benefits. It takes much less preparation time to visualize virtual paints than painting a real vehicle with a real paint. It gives a better opportunity to visualize vehicles with a new paint than if only paint samples or static photographs are used. It saves money by limiting a number of vehicles that need to be painted for the automotive paint evaluation. Models with paint for evaluation need not be stored, or shipped to viewing facilities. Preliminary automotive paint selection may be conducted using a computer-generated visualization for initial screening of potential paints. Consumer selection of a paint and finish may be conducted, for example, at a dealership prior to a vehicle purchase.
Accurate simulations of paint qualities lend themselves to increased usage of computer-generated objects in the paint selection and development process. A realistic paint model combined with accurate rendering allows a user to make adjustments to various factors defining the simulated paint, which may in turn be used to specify the color and characteristics of a real paint or set of paints.
Truly realistic paints need a more accurate description than simply the red/green/blue color components used in many graphics programs. The effect of paint composition should be captured. One should be able to distinguish between, for example, solid paints, paints with small flakes, paints with medium flakes, paints with coarse flakes, and pearlescent paints. One should be able to gather an accurate sense of the flake size and dimensions. Computer-generated paint representation should capture precisely the static and dynamic characteristics of the paint. Static aspects of the paint include paint color, structure, flop, reflectivity, texture, flakes, flake size and color, clarity of xe2x80x9chot spotsxe2x80x9d, specular reflections, diffuse components, emission components, paint shininess, and clear coat finish. Dynamic properties include color travel, highlight travel, change of specular reflectivity and hot spot travel. All these characteristics should be mapped and represented properly in a virtual paint.
Every paint should reflect the surrounding environment differently, since each paint has its own reflectivity characteristics that are due to its unique composition. Reflectivity characteristics in a virtual paint should be distinguishable when viewing a series of simulated paints on a computer-generated model. Reflectivity characteristics of the paint vary with the environmental setting, and so the environment reflections should vary from paint to paint in a rendered, static object in changing environmental settings.
Realistic simulation of paint should be based on a description of a paint that includes paint characteristics, number of layers, layer composition, color, and components. If the paint has flakes, the computer-generated visualization of that paint should represent those flakes, their behavior, and their properties such as their size, color, material, density, distribution and reflectivity. In the case of metallic paint, the computer-generated visualization of that paint should realistically capture the effect of metallic properties.
Representation of computer-generated paint should be updated dynamically as if it were a real paint. If the painted surface changes in position with respect to surroundings or lighting conditions, or if the viewer changes position with respect to the surface, the computer-generated paint should be updated realistically and correctly. The quality and clearness of reflections of the environment reflected from the surfaces of a vehicle should be captured, and their dynamics should change while the vehicle changes its position with respect to the sun and the viewer, or when undergoing other types of lighting condition alterations.
Criterion such as computer-generated realistically looking paint means that for any paint, its unique properties such as texture, color, reflectivity, flakes, flop and gloss are captured and represented correctly in a computer-generated virtual environment. Virtual environments are generated using virtual reality technology. Virtual reality may be a tool for evaluating and selecting paints, requiring that virtual reality display devices as well as projection screens be adjusted or calibrated to accurately convey paint color and paint characteristics.
Technology to enhance realism of computer-generated visualization of exterior automotive paints are based, in part, on producing reflection texture maps that make a computer-generated vehicle look realistic and show more realistic reflections of the environment on the paint. These reflections are captured with computer graphics by using semi-transparent environment texture maps applied to a computer-generated object. An environment texture map may be described by a collection of quadruplets, where each quadruple is associated with a particular point or pixel of the map. The quadruplet contains three-color components: red, green, and blue; and a transparency component, called xe2x80x9calphaxe2x80x9d. Typical environment maps are evenly semi-transparent at each point or pixel of the map. However, different algorithms may be used to compute values of a transparency component for each pixel of the environment map. The algorithm may control the distribution of transparency throughout the map. The algorithm may vary the amount of reflections from paint to paint, to account for the reflectivity differences of each paint. The transparency distribution algorithm for environment maps should generate correct paint results in the computer-generated vehicle visualization, rather than just another abstract reflection effect.
Multiple reflection maps may be used to allow various viewing positions, where a user may change a location and view a vehicle from virtually any location in space, with smooth interpolations between various views. The algorithm should use more than one texture map and transparency map to create realistic environmental reflections from multiple orientations, with the paint along with its characteristics and reflections looking correct. The paint should be represented and visualized accurately in each position and should be generated rather quickly.
The objective of the current invention is the development of a method for visualizing automotive paints applied to computer-generated three-dimensional virtual vehicles. The results should be accurate and realistic, combining knowledge about computer graphics and knowledge about color, paint, and automotive surfaces.
Therefore, it would be desirable to provide a method and system for realistic visualization of paint on a computer-generated object, thus overcoming the aforementioned and other disadvantages.
One aspect of the invention provides a method for visualizing paint on a computer-generated object. Adjustments may be made to a color environment reflection map based on a reflective quality rating of the paint. Adjustments may also be made to a transparency map based on the reflective quality rating of the paint. The adjusted color reflection and transparency maps then may be combined, and be applied to the computer-generated object.
The color environment reflection map may comprise at least one photographic image of a reflective sphere in a selected environment. The photographic images of the reflective sphere may be taken from more than one viewing angle.
Additionally, the color environment reflection map may be adjusted based on a base color table that includes primary component information of a particular paint. This information may be based on spectrometer and chromometer measurements. The reflection map also may be adjusted based on at least one paint texture map. The paint texture map may be based on a paint description model corresponding to at least one member from a group consisting of flake size, flake density, flake distribution, flake composition, pearlescence, color travel, specular reflectivity, diffusivity, emissivity, highlights, gloss, and shininess.
The computer-generated object may be rendered and displayed. The display device may be a stereographic virtual reality device. The display device may be a screen or it may be an array of screens.
Another aspect of the invention is a computer usable medium that includes a program for rendering paint on a computer-generated object. The program comprises computer program code that combines an environment reflection map and a transparency map after they have been adjusted based on a reflective quality rating of a paint.
The program code may provide a base color table and adjust the color environment reflection map based on the table. The program code also may adjust the reflection map based on at least one paint texture map. The computer usable medium may comprise computer program code for rendering the computer-generated object and displaying the computer-generated object using a display device.
Another aspect of the invention provides a method for evaluating paint on a mobile vehicle. The evaluation method comprises rating a plurality of paints based on reflective quality; selecting one of the paints for simulation; providing a computer-generated image of the mobile vehicle; adjusting a color environment reflection map and a transparency map based on the reflective quality rating associated with the selected paint; rendering the image with the adjusted maps; and displaying the image. Additionally, the color environment reflection map may be adjusted based on a base color table. The color environment reflection map may be adjusted based on one or more texture maps.
Another aspect of the invention provides a system for evaluating paint on a mobile vehicle. This system provides means for rating a plurality of paints based on reflective quality; for selecting one of the paints for simulation; for providing a computer-generated image of the mobile vehicle; for adjusting a color environment reflection map and a transparency map based on the reflective quality rating associated with the selected paint; for rendering the image with the adjusted maps; and for displaying the rendered image. The system may further comprise means for adjusting the color environment reflection map based on a base color table, and means for adjusting the color environment reflection map based on at least one paint texture map.
The aforementioned, and other features and advantages of the invention will become further apparent from the following detailed description of the presently preferred embodiments, read in conjunction with the accompanying drawings. The detailed description and drawings are merely illustrative of the invention rather than limiting, the scope of the invention being defined by the appended claims and equivalents thereof.